Image sensors are widely used in image capturing modules such as digital camera modules in order to convert optical image signals of an object into electronic signals. In order to protect the image sensor from contamination or pollution (i.e. from dust or water vapor), the image sensor is generally sealed in a structural package.
An image sensor chip package made according to a typical packaging method is illustrated in FIG. 1. The packaging method includes the following steps: firstly, a plurality of bracket-shaped conductors 10 are provided. Secondly, molten plastic is injected to partially enclose the conductors 10, thereby forming a base 11, with some surfaces of the conductors 10 being exposed outside of the base 11. Thirdly, a ring-like middle portion 12 is formed on the base 11 by means of injection molding. The base 11 and the middle portion 12 cooperatively form a space 13. Fourthly, an image sensor 15 having a plurality of pads 14 is disposed on the base 11 in the space 13. Fifthly, a plurality of bonding wires 16 are provided to connect the pads 14 and the conductors 10. Finally, a cover 17 is secured to the top of the middle portion 12 with an adhesive, thereby hermetically sealing the space 13 and allowing light beams to pass therethrough.
In the process of bonding the wires 16, each wire 16 needs to be connected with one conductor 10. As a result, the space 13 needs to be relatively large, for allowing movement of a wire bonding tool therein. This method of bonding wires 16 is complex and expensive. In addition, the relatively large volume of the image sensor chip package allows more dust particles to adhere to the cover 17, the middle portion 12, and the base 11. Thus, more dust particles are liable to drop onto the image sensor 15. The dust particles may obscure part of the optical path to the image sensor 15, and produce errors in the image sensing process. As a result, the quality and/or reliability of the image sensor chip package may be impaired.
Therefore, a new image sensor chip packaging method is desired in order to overcome the above-described shortcomings.